ANTHROPOGENIC IMPACT ON THE DEVELOPMENT OF RESISTANCE TO ANTIBIOTICS IN MICROORGANISMS OF THE UZH RIVER (UKRAINE)

Abstract

Background. An excessive use of antibiotics in human and veterinary medicine contributes to the additional selection pressure on microorganisms and leads to the rapid spread of dangerous microorganisms with an increased ability to resist numerous classes of antibiotics. Aquatic ecosystems are among the main resistance genes pools, and therefore should be subject to mandatory control. Apparently, the spread of antibiotic-resistant microorganisms depends not only on the concentration of antibiotics entering water bodies with wastewaters, but also on other qualitative characteristics of the aquatic environment.
The aim of this work was to determine the correlation between the content of heavy metals (Cu, Ni, Zn, Cr) and nitrogen compounds (NO₃, NO₂ and NH₄) in water and the distribution of antibiotic resistant microorganisms in research sites on the Uzh River (Ukraine) that are affected by anthropogenic impact. Based on our seasonal moni­toring during 2016–2017, which included determining the content of nitrogen compounds and heavy metals in the research sites, and as a result of the study on the microbiocenosis structure with a subsequent determination of antibiotic sensitivity of the dominant strains isolated from water samples, we conducted analysis of the correlation between the concentrations of these substances and the distribution of antibiotic resistant strains. This enabled us to identify the potential factors that contribute to the deve­lopment of antibiotic resistance in microorganisms.
Material and methods. The relationship between the chemical parameters and the percentage of antibiotic-resistant microorganisms was determined using the linear Pearson’s correlation coefficient (r). Statistical data processing was performed using the software package „Microsoft Excel”. Results with a p-value less than 0.05 (р<0.05) were considered statistically significant.
Results. The relationship between the level of antibiotic resistance of microorga­nisms and chemical pollution has been established. A strong correlation between excessive concentrations of Zn and elevated concentrations of Ni relative to background va­lues and increased antibiotic resistance is characteristic of the area under conditions of technogenic transformation. In the urbanised area, a relationship between an increase in antibiotic resistance and Ni concentrations was observed in the studied samples. In the agricultural area, a strong correlation between nitrogen compounds, namely nitra­tes, and an increase in antibiotic resistance of microorganisms has been established.
Conclusion. The obtained results that establish a correlation between the concentrations of chemical substances in water and the activation of antibiotic resistance in microorganisms can indicate the degree of aquatic ecosystems transformation under anthropogenic impact. Thus, a comprehensive monitoring of the environmental quality of aquatic ecosystems is essential.